The present invention relates to tape recorders and in particular to a method and apparatus for use in tape recorders to generate an audible warning sound as the tape end is approached during recording.
When recording, it is highly desirable to be able to automatically determine when the end of the tape is being approached and only a small supply or no supply of useable tape is available for continued recording. Such a warning could serve to prevent the loss of date or information.
Heretofore, several systems have been developed for generating such an end of the tape signal. In one type of prior art arrangement, mechanical or electrical counters are used to determine the amount of tape used and hence the amount of remaining tape. It has also been suggested to provide special markers on the tape, for example, a light reflecting or light transparent section, which causes light to intrude upon a photo detector cell when the specially treated tape portion passes a light source. In still another arrangement an audible signal is generated as the tape end is approached by means of a separate signal generator which is switched on by means of a foil coated section at the end of the tape. The foil coated section bridges a set of contacts to activate the signal generator which is used in conjunction with the recorder loudspeaker.
The principal disadvantage of the prior art methods and devices are that they require additional components and hence add to the expense of the recorder. In addition, the additional components take up space. This poses a special problem with regard to hand held dictating devices and particularly miniature tape recorders. In such miniature tape recorders it is not readily possible to install the additional means required of the prior art devices such as counters, distance meters, photo detectors, signal generators and the like because of the very limited space restrictions. In addition, it is important to attract the attention of the person operating the dictating device as the end of the tape approaches and such operator cannot always observe a mechanical or optical warning such as the running of a cassette. It is far more desirable to provide an audible warning.
In view of the above, it is the principal object of the present invention to provide a simple means of generating an audible signal as the end of the tape is approached in a tape recording device.
A further object is to provide such a device that utilizes the existing components of the recording machine and does not add to the size or bulk of the machine.
A still further object is to provide such a tape end warning device which operates audibly and does not require that the operator watch a meter or other visual warning indicator.